Here's a link to an article, from PsychCentral's archives, on the subject of what to do when your friend is in an abusive relationship:

https://pro.psychcentral.com/recover...-relationship/

And then here are links to some other articles written to be of help to individuals who are in abusive relationships. Perhaps, if your friend is willing, you could share them with her:

https://psychcentral.com/blog/21-war...-relationship/

https://psychcentral.com/blog/5-ways...-relationship/

https://psychcentral.com/blog/in-an-...steps-to-take/

https://psychcentral.com/blog/you-de...dium=popular17

https://psychcentral.com/blog/trusti...dium=popular17

https://psychcentral.com/blog/how-to...-relationship/